HP-15c has been re-issued, available now

But unavailable outside the US :(

If it's anything like the 300s or the 35s reissue, it's going to be crap. Just about anything coming out of HP since the HP48 is utter shit.

For ref the 300s buttons don't work properly and the OS is simply 100% stolen from Casio FX-series which are 1/3 the price. The 35s is buggy as anything and can't even display a single FP value accurately without having to scroll. The HP49G is better but still to expensive.

Save some cash: buy a TI89 or a second hand TI-92+ if you can be bothered to carry it around.